[clang] [clang][coverage] fixing "if constexpr" and "if consteval" coverage report (PR #77214)
Hana Dusíková via cfe-commits
cfe-commits at lists.llvm.org
Mon Jan 8 02:57:04 PST 2024
https://github.com/hanickadot updated https://github.com/llvm/llvm-project/pull/77214
>From 413517b2a1d4e45b6c58ab282c7990e83f429ab9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Hana=20Dusi=CC=81kova=CC=81?= <hanicka at hanicka.net>
Date: Mon, 8 Jan 2024 11:54:45 +0100
Subject: [PATCH] [coverage] fix incorrect coverage reporting for "if
constexpr" and "if consteval"
---
clang/docs/ReleaseNotes.rst | 3 +
clang/include/clang/AST/Stmt.h | 6 +-
clang/lib/CodeGen/CoverageMappingGen.cpp | 13 +++-
clang/lib/Sema/TreeTransform.h | 10 ++-
clang/test/CoverageMapping/if.cpp | 86 +++++++++++++++++++-----
5 files changed, 96 insertions(+), 22 deletions(-)
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index c9b577bd549b1e..c36e051d055b72 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -696,6 +696,9 @@ Bug Fixes in This Version
- Clang now accepts recursive non-dependent calls to functions with deduced
return type.
Fixes (`#71015 <https://github.com/llvm/llvm-project/issues/71015>`_)
+- Clang now emits correct source location for code-coverage regions in `if constexpr`
+ and `if consteval` branches.
+ Fixes (`#54419 <https://github.com/llvm/llvm-project/issues/54419>`_)
Bug Fixes to Compiler Builtins
diff --git a/clang/include/clang/AST/Stmt.h b/clang/include/clang/AST/Stmt.h
index da7b37ce0e1211..e1fde24e647789 100644
--- a/clang/include/clang/AST/Stmt.h
+++ b/clang/include/clang/AST/Stmt.h
@@ -1631,8 +1631,10 @@ class CompoundStmt final
SourceLocation RB);
// Build an empty compound statement with a location.
- explicit CompoundStmt(SourceLocation Loc)
- : Stmt(CompoundStmtClass), LBraceLoc(Loc), RBraceLoc(Loc) {
+ explicit CompoundStmt(SourceLocation Loc) : CompoundStmt(Loc, Loc) {}
+
+ CompoundStmt(SourceLocation Loc, SourceLocation EndLoc)
+ : Stmt(CompoundStmtClass), LBraceLoc(Loc), RBraceLoc(EndLoc) {
CompoundStmtBits.NumStmts = 0;
CompoundStmtBits.HasFPFeatures = 0;
}
diff --git a/clang/lib/CodeGen/CoverageMappingGen.cpp b/clang/lib/CodeGen/CoverageMappingGen.cpp
index bf227386a71b78..b245abd16c3f4a 100644
--- a/clang/lib/CodeGen/CoverageMappingGen.cpp
+++ b/clang/lib/CodeGen/CoverageMappingGen.cpp
@@ -1712,7 +1712,11 @@ struct CounterCoverageMappingBuilder
extendRegion(S->getCond());
Counter ParentCount = getRegion().getCounter();
- Counter ThenCount = getRegionCounter(S);
+
+ // If this is "if !consteval" the then-branch will never be taken, we don't
+ // need to change counter
+ Counter ThenCount =
+ S->isNegatedConsteval() ? ParentCount : getRegionCounter(S);
if (!S->isConsteval()) {
// Emitting a counter for the condition makes it easier to interpret the
@@ -1729,7 +1733,12 @@ struct CounterCoverageMappingBuilder
extendRegion(S->getThen());
Counter OutCount = propagateCounts(ThenCount, S->getThen());
- Counter ElseCount = subtractCounters(ParentCount, ThenCount);
+ // If this is "if consteval" the else-branch will never be taken, we don't
+ // need to change counter
+ Counter ElseCount = S->isNonNegatedConsteval()
+ ? ParentCount
+ : subtractCounters(ParentCount, ThenCount);
+
if (const Stmt *Else = S->getElse()) {
bool ThenHasTerminateStmt = HasTerminateStmt;
HasTerminateStmt = false;
diff --git a/clang/lib/Sema/TreeTransform.h b/clang/lib/Sema/TreeTransform.h
index c8c5a51bf9f94e..19266a7ffa2fe0 100644
--- a/clang/lib/Sema/TreeTransform.h
+++ b/clang/lib/Sema/TreeTransform.h
@@ -7732,7 +7732,11 @@ TreeTransform<Derived>::TransformIfStmt(IfStmt *S) {
if (Then.isInvalid())
return StmtError();
} else {
- Then = new (getSema().Context) NullStmt(S->getThen()->getBeginLoc());
+ // Discarded branch is replaced with empty CompoundStmt so we can keep
+ // proper source location for start and end of original branch, so
+ // subsequent transformations like CoverageMapping work properly
+ Then = new (getSema().Context)
+ CompoundStmt(S->getThen()->getBeginLoc(), S->getThen()->getEndLoc());
}
// Transform the "else" branch.
@@ -7741,6 +7745,10 @@ TreeTransform<Derived>::TransformIfStmt(IfStmt *S) {
Else = getDerived().TransformStmt(S->getElse());
if (Else.isInvalid())
return StmtError();
+ } else if (S->getElse() && ConstexprConditionValue &&
+ *ConstexprConditionValue) {
+ Else = new (getSema().Context)
+ CompoundStmt(S->getElse()->getBeginLoc(), S->getElse()->getEndLoc());
}
if (!getDerived().AlwaysRebuild() &&
diff --git a/clang/test/CoverageMapping/if.cpp b/clang/test/CoverageMapping/if.cpp
index 65e3d62df79db4..cc18f791c2f79e 100644
--- a/clang/test/CoverageMapping/if.cpp
+++ b/clang/test/CoverageMapping/if.cpp
@@ -23,19 +23,29 @@ void foo() { // CHECK-NEXT: Gap,File 0, [[@LINE+1]]:21 -> [[@
} // CHECK-NEXT: [[@LINE-2]]:9 -> [[@LINE-1]]:5 = #1
// CHECK-NEXT: [[@LINE-2]]:5 -> [[@LINE-2]]:8 = #1
-// FIXME: Do not generate coverage for discarded branches in if consteval and if constexpr statements
-constexpr int check_consteval(int i) {
- if consteval {
- i++;
- }
- if !consteval {
- i++;
- }
- if consteval {
- return 42;
- } else {
- return i;
- }
+// FIXME: Do not generate coverage for discarded branches in if constexpr
+// CHECK-LABEL: _Z16check_constexprAi:
+int check_constexprA(int i) { // CHECK-NEXT: [[@LINE]]:29 -> {{[0-9]+}}:2 = #0
+ // CHECK-NEXT: [[@LINE+2]]:16 -> [[@LINE+2]]:20 = #0
+ // CHECK-NEXT: Branch,File 0, [[@LINE+1]]:16 -> [[@LINE+1]]:20 = 0, 0
+ if constexpr(true) { // CHECK-NEXT: Gap,File 0, [[@LINE]]:21 -> [[@LINE]]:22 = #1
+ i *= 3; // CHECK-NEXT: [[@LINE-1]]:22 -> [[@LINE+1]]:4 = #1
+ } else { // CHECK-NEXT: Gap,File 0, [[@LINE]]:4 -> [[@LINE]]:10 = (#0 - #1)
+ i *= 5; // CHECK-NEXT: [[@LINE-1]]:10 -> [[@LINE+1]]:4 = (#0 - #1)
+ }
+ return i;
+}
+
+// CHECK-LABEL: _Z16check_constexprBi:
+int check_constexprB(int i) { // CHECK-NEXT: [[@LINE]]:29 -> {{[0-9]+}}:2 = #0
+ // CHECK-NEXT: [[@LINE+2]]:16 -> [[@LINE+2]]:21 = #0
+ // CHECK-NEXT: Branch,File 0, [[@LINE+1]]:16 -> [[@LINE+1]]:21 = 0, 0
+ if constexpr(false) { // CHECK-NEXT: Gap,File 0, [[@LINE]]:22 -> [[@LINE]]:23 = #1
+ i *= 3; // CHECK-NEXT: File 0, [[@LINE-1]]:23 -> [[@LINE+1]]:4 = #1
+ } else { // CHECK-NEXT: Gap,File 0, [[@LINE]]:4 -> [[@LINE]]:10 = (#0 - #1)
+ i *= 5; // CHECK-NEXT: File 0, [[@LINE-1]]:10 -> [[@LINE+1]]:4 = (#0 - #1)
+ }
+ return i;
}
// CHECK-LABEL: main:
@@ -75,10 +85,6 @@ int main() { // CHECK: File 0, [[@LINE]]:12 -> {{[0-9]+}}:2 =
// CHECK-NEXT: File 0, [[@LINE+1]]:14 -> [[@LINE+1]]:20 = #6
i = i == 0?i + 12:i + 10; // CHECK-NEXT: File 0, [[@LINE]]:21 -> [[@LINE]]:27 = (#0 - #6)
- // GH-57377
- constexpr int c_i = check_consteval(0);
- check_consteval(i);
-
// GH-45481
S s;
s.the_prop = 0? 1 : 2; // CHECK-NEXT: File 0, [[@LINE]]:16 -> [[@LINE]]:17 = #0
@@ -98,3 +104,49 @@ int main() { // CHECK: File 0, [[@LINE]]:12 -> {{[0-9]+}}:2 =
void ternary() {
true ? FOO : FOO; // CHECK-NOT: Gap,{{.*}}, [[@LINE]]:8 ->
}
+
+// FIXME: Do not generate coverage for discarded branches in if consteval
+// GH-57377
+// CHECK-LABEL: _Z16check_constevalAi:
+constexpr int check_constevalA(int i) { // CHECK-NEXT: [[@LINE]]:39 -> {{[0-9]+}}:2 = #0
+ if consteval {
+ i *= 3; // CHECK-NEXT: [[@LINE-1]]:16 -> [[@LINE+1]]:4 = #1
+ } else { // CHECK-NEXT: Gap,File 0, [[@LINE]]:4 -> [[@LINE]]:10 = #0
+ i *= 5; // CHECK-NEXT: [[@LINE-1]]:10 -> [[@LINE+1]]:4 = #0
+ }
+ return i; // CHECK-NEXT: [[@LINE]]:3 -> [[@LINE]]:11 = (#0 + #1)
+}
+
+// CHECK-LABEL: _Z16check_constevalBi:
+constexpr int check_constevalB(int i) { // CHECK-NEXT: [[@LINE]]:39 -> {{[0-9]+}}:2 = #0
+ if !consteval {
+ i *= 3; // CHECK-NEXT: [[@LINE-1]]:17 -> [[@LINE+1]]:4 = #0
+ } else { // CHECK-NEXT: Gap,File 0, [[@LINE]]:4 -> [[@LINE]]:10 = 0
+ i *= 5; // CHECK-NEXT: [[@LINE-1]]:10 -> [[@LINE+1]]:4 = 0
+ }
+ return i;
+}
+
+// CHECK-LABEL: _Z16check_constevalCi:
+constexpr int check_constevalC(int i) { // CHECK-NEXT: [[@LINE]]:39 -> {{[0-9]+}}:2 = #0
+ if consteval {
+ i *= 3; // CHECK-NEXT: [[@LINE-1]]:16 -> [[@LINE+1]]:4 = #1
+ }
+ return i; // CHECK-NEXT: [[@LINE]]:3 -> [[@LINE]]:11 = (#0 + #1)
+}
+
+// CHECK-LABEL: _Z16check_constevalDi:
+constexpr int check_constevalD(int i) { // CHECK-NEXT: [[@LINE]]:39 -> {{[0-9]+}}:2 = #0
+ if !consteval {
+ i *= 3; // CHECK-NEXT: [[@LINE-1]]:17 -> [[@LINE+1]]:4 = #0
+ }
+ return i;
+}
+
+int instantiate_consteval(int i) {
+ i *= check_constevalA(i);
+ i *= check_constevalB(i);
+ i *= check_constevalC(i);
+ i *= check_constevalD(i);
+ return i;
+}
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